1. Field of the Invention
The present invention relates to an exhaust system for a motorcycle, and to a motorcycle incorporating same. More particularly, the present invention relates to a distributive arrangement of components of the exhaust system in a motorcycle.
2. Description of the Background Art
There are several known exhaust systems for a motorcycle. The exhaust systems emit exhaust gas from an engine into the air via an exhaust pipe and a silencer. The engine is generally arranged between front and rear wheels of the motorcycle.
An example of such known exhaust system for a motorcycle is disclosed in the Japanese Patent document JP-A No. 2007-91180, in which a first muffler (54) and a second muffler (55) are arranged parallel to each other at a position below the engine, and in which an exhaust pipe extending from the engine is connected to the second muffler (see FIGS. 1 and 4 thereof).
According to the Japanese Patent document JP-A No. 2007-91180 (as shown in the FIG. 4 thereof), the exhaust system includes a plural (four) exhaust pipes (39A to 39D) extending in a longitudinal direction of a vehicle body. The exhaust pipes (39A-39D) are connected to the second muffler (55) at rear portion thereof via a U-shaped bent second connecting pipe (52), and are operatively connected to the first muffler (54) via a front end portion of the second muffler (55). The second muffler (55) is arranged in the longitudinal direction of the vehicle body. The first muffler (54) is arranged in series with the second muffler (55) in the longitudinal direction of the vehicle body.
A downstream portion (a portion in front of the U-shaped portion of the bent second connecting pipe in the rear of the vehicle body) of the first muffler 54 communicates with an expansion chamber 69. The second connecting pipe (52) is connected to a third muffler 57 (see FIG. 1 of the Japanese Patent document JP-A No. 2007-91180) arranged in the rear of the vehicle body.
The exhaust system, as disclosed in the Japanese Patent document JP-A No. 2007-91180 (see FIG. 4 thereof), is configured such that the exhaust pipes 39A-39D and connecting pipe (52) are arranged on one side (right side) of the vehicle body in a vehicle width direction, whereas the first muffler and the second muffler, each respectively having large volume, are arranged in series on the other side (left side) of the vehicle body in the vehicle width direction.
Since the exhaust pipes and connecting/collecting pipes are arranged on one side and the mufflers (having large volumes) are arranged on the other side, the length of the exhaust system in a longitudinal direction of the vehicle is disadvantageously lengthened (increased), particularly when the exhaust system is arranged below the engine of the motorcycle, the length of the exhaust system is further increased.
As a result of increasing a length of the exhaust system, arranged below the engine in the longitudinal direction of the vehicle, a wheelbase of the motorcycle is disadvantageously increased.
The present invention has been made to overcome such drawbacks of the existing exhaust system for the motorcycle. Accordingly, it is one of the objects of the present invention to provide an exhaust system for a motorcycle, in which the exhaust system is arranged below the engine, and in which components of the exhaust system are arranged such that a length of the exhaust system is reduced in comparison to the existing systems so as to achieve a lateral balance of the exhaust system in a vehicle width direction, and to enable the concentration of the mass of the exhaust system at a desired position.